Irregular Pore Networks and Mechanical Effects during Drying of Porous Media

A new approach is proposed to investigate the influence of liquid phase distributions on damage and deformation of porous materials during convective drying. The solid phase of the porous material is represented by a cubic packing of mono-sized spherical particles that are bonded together at their contacts. Liquid phase distributions in the void space are obtained from isothermal drying simulations for a complementary pore network. In a one-way coupling approach, capillary forces are computed over time from the filling state of pores and applied as loads on each particle in Discrete Element Method (DEM). Micro-cracks induced by bond breakage are observed in stiff material whereas soft material tends to shrink reversibly without damage. As a next step, an irregular pore network model for drying of arbitrary aggregates of mono-sized spherical particles is introduced. The network structure is generated by Voronoi tessellation of the aggregate and by designating the Voronoi edges as interconnected cylindrical pores. Then isothermal pore network drying model is generalized to the new irregular structure and thus drying simulations are carried out. Capillary forces computation is also devised to account for the irregular network structure.